Thanks Scott, that's good to know. I suppose the expansion modules, like the ESPSM6 are just relays and the limit on how many valves the controller will switch is limited by the power supply to the controller and the draw of the valve? Not that I would probably ever want to try 3 or more valves. It's already switching a master valve along with the zone valve, plus a booster pump which probably doesn't pull much current off the 24V. I don't know what type valves I have, I need to look.
Actually, I was thinking of sticking with the 15VAN nozzles, with them adjusted down to only spray about 6' (and I already have them and the rotary's spray 8' min. plus the prs) I need to measure one for GPH and figure the prec rate, but I bet with that 15' nozzle shut down that amount I could probably run 2 zones of 5 or 6 heads easily of course for a longer time. All the nozzles are running 180° or less. I must be running about 60 or more PSI (booster pump with private well) because the 6VAN and 8VAN both spray out over 8'. What I like about turning down the 15VAN is it sprays up so it gets over the perennials better than the flat spraying 6 or 8VAN which hit the plants and stop there. I have one zone with 9 - 15VAN in it(most at 180°) and there's no loss of pressure there that I can tell.